1. Field of the Invention
The present invention relates to controls for X-Y shifters and, in particular, to controls for X-Y shifters utilizing independent and occasionally simultaneous control of the motors used to control the X--X and Y--Y shift positions.
2. Description of the Prior Art
Change-gear transmissions and so-called X-Y shifting devices therefor are well known in the prior art. Briefly, X-Y shifters are devices which control the X--X (or selection directional) and the Y--Y (or engage/not-engaged directional) position of a shift member, such as a shift finger or the like. Typically, two separate fluid or electric motors are used to control the X--X and Y--Y positions.
The X-Y shifters are mounted to the transmission and are manually controlled as "shift-by-wire" slave devices or are under the control of a system controller of a fully or partially automated transmission system.
X-Y shifters may be seen by reference to U.S. Pat. Nos. 4,621,328; 4,784,007; 4,796,485; 4,817,468; 4,821,590 and 4,873,590, the disclosures of which are incorporated herein by reference.
The current X-Y shifters use discreet, single-action controls which limit positioning of the shift member to only one axis at a time and require delays for coast-down, stopping and centering functions. This may result in shifts which are more time-consuming than desirable.